148 ideas
13466 | We are all post-Kantians, because he set the current agenda for philosophy [Hart,WD] |
13477 | The problems are the monuments of philosophy [Hart,WD] |
13515 | To study abstract problems, some knowledge of set theory is essential [Hart,WD] |
3508 | Correspondence to the facts HAS to be the aim of enquiry [Searle] |
13469 | Tarski showed how we could have a correspondence theory of truth, without using 'facts' [Hart,WD] |
13504 | Truth for sentences is satisfaction of formulae; for sentences, either all sequences satisfy it (true) or none do [Hart,WD] |
13503 | A first-order language has an infinity of T-sentences, which cannot add up to a definition of truth [Hart,WD] |
13500 | Conditional Proof: infer a conditional, if the consequent can be deduced from the antecedent [Hart,WD] |
10987 | Three traditional names of rules are 'Simplification', 'Addition' and 'Disjunctive Syllogism' [Read] |
13502 | ∃y... is read as 'There exists an individual, call it y, such that...', and not 'There exists a y such that...' [Hart,WD] |
11004 | Necessity is provability in S4, and true in all worlds in S5 [Read] |
11018 | There are fuzzy predicates (and sets), and fuzzy quantifiers and modifiers [Read] |
11011 | Same say there are positive, negative and neuter free logics [Read] |
13456 | Set theory articulates the concept of order (through relations) [Hart,WD] |
13497 | Nowadays ZFC and NBG are the set theories; types are dead, and NF is only useful for the whole universe [Hart,WD] |
13443 | ∈ relates across layers, while ⊆ relates within layers [Hart,WD] |
13442 | Without the empty set we could not form a∩b without checking that a and b meet [Hart,WD] |
13493 | In the modern view, foundation is the heart of the way to do set theory [Hart,WD] |
13495 | Foundation Axiom: an nonempty set has a member disjoint from it [Hart,WD] |
13461 | We can choose from finite and evident sets, but not from infinite opaque ones [Hart,WD] |
13462 | With the Axiom of Choice every set can be well-ordered [Hart,WD] |
13516 | If we accept that V=L, it seems to settle all the open questions of set theory [Hart,WD] |
11020 | Realisms like the full Comprehension Principle, that all good concepts determine sets [Read] |
13441 | Naïve set theory has trouble with comprehension, the claim that every predicate has an extension [Hart,WD] |
13494 | The iterative conception may not be necessary, and may have fixed points or infinitely descending chains [Hart,WD] |
13457 | A 'partial ordering' is irreflexive and transitive; the sets are ordered, but not the subsets [Hart,WD] |
13458 | A partial ordering becomes 'total' if any two members of its field are comparable [Hart,WD] |
13460 | 'Well-ordering' must have a least member, so it does the natural numbers but not the integers [Hart,WD] |
13490 | Von Neumann defines α<β as α∈β [Hart,WD] |
13481 | Maybe sets should be rethought in terms of the even more basic categories [Hart,WD] |
10986 | Not all validity is captured in first-order logic [Read] |
10972 | The non-emptiness of the domain is characteristic of classical logic [Read] |
11024 | Semantics must precede proof in higher-order logics, since they are incomplete [Read] |
10985 | We should exclude second-order logic, precisely because it captures arithmetic [Read] |
10970 | A theory of logical consequence is a conceptual analysis, and a set of validity techniques [Read] |
10984 | Logical consequence isn't just a matter of form; it depends on connections like round-square [Read] |
10973 | A theory is logically closed, which means infinite premisses [Read] |
11007 | Quantifiers are second-order predicates [Read] |
13506 | The universal quantifier can't really mean 'all', because there is no universal set [Hart,WD] |
10978 | In second-order logic the higher-order variables range over all the properties of the objects [Read] |
10971 | A logical truth is the conclusion of a valid inference with no premisses [Read] |
13505 | Model theory studies how set theory can model sets of sentences [Hart,WD] |
13511 | Model theory is mostly confined to first-order theories [Hart,WD] |
13512 | Modern model theory begins with the proof of Los's Conjecture in 1962 [Hart,WD] |
13513 | Models are ways the world might be from a first-order point of view [Hart,WD] |
10988 | Any first-order theory of sets is inadequate [Read] |
13496 | First-order logic is 'compact': consequences of a set are consequences of a finite subset [Hart,WD] |
10974 | Compactness is when any consequence of infinite propositions is the consequence of a finite subset [Read] |
10975 | Compactness does not deny that an inference can have infinitely many premisses [Read] |
10977 | Compactness blocks the proof of 'for every n, A(n)' (as the proof would be infinite) [Read] |
10976 | Compactness makes consequence manageable, but restricts expressive power [Read] |
13484 | Berry's Paradox: we succeed in referring to a number, with a term which says we can't do that [Hart,WD] |
13482 | The Burali-Forti paradox is a crisis for Cantor's ordinals [Hart,WD] |
11014 | Self-reference paradoxes seem to arise only when falsity is involved [Read] |
13507 | The machinery used to solve the Liar can be rejigged to produce a new Liar [Hart,WD] |
13459 | The less-than relation < well-orders, and partially orders, and totally orders the ordinal numbers [Hart,WD] |
13491 | The axiom of infinity with separation gives a least limit ordinal ω [Hart,WD] |
13463 | There are at least as many infinite cardinals as transfinite ordinals (because they will map) [Hart,WD] |
13492 | Von Neumann's ordinals generalise into the transfinite better, because Zermelo's ω is a singleton [Hart,WD] |
13446 | 19th century arithmetization of analysis isolated the real numbers from geometry [Hart,WD] |
13509 | We can establish truths about infinite numbers by means of induction [Hart,WD] |
11025 | Infinite cuts and successors seems to suggest an actual infinity there waiting for us [Read] |
13474 | Euclid has a unique parallel, spherical geometry has none, and saddle geometry has several [Hart,WD] |
10979 | Although second-order arithmetic is incomplete, it can fully model normal arithmetic [Read] |
10980 | Second-order arithmetic covers all properties, ensuring categoricity [Read] |
10997 | Von Neumann numbers are helpful, but don't correctly describe numbers [Read] |
13471 | Mathematics makes existence claims, but philosophers usually say those are never analytic [Hart,WD] |
3473 | Reduction can be of things, properties, ideas or causes [Searle] |
3532 | Solidity in a piston is integral to its structure, not supervenient [Maslin on Searle] |
3533 | Is supervenience just causality? [Searle, by Maslin] |
13488 | Mass words do not have plurals, or numerical adjectives, or use 'fewer' [Hart,WD] |
3454 | Reality is entirely particles in force fields [Searle] |
11016 | Would a language without vagueness be usable at all? [Read] |
11019 | Supervaluations say there is a cut-off somewhere, but at no particular place [Read] |
11012 | A 'supervaluation' gives a proposition consistent truth-value for classical assignments [Read] |
11013 | Identities and the Indiscernibility of Identicals don't work with supervaluations [Read] |
3471 | Some properties depend on components, others on their relations [Searle] |
3472 | Fully 'emergent' properties contradict our whole theory of causation [Searle] |
10995 | A haecceity is a set of individual properties, essential to each thing [Read] |
11001 | Equating necessity with truth in every possible world is the S5 conception of necessity [Read] |
10992 | The point of conditionals is to show that one will accept modus ponens [Read] |
10989 | The standard view of conditionals is that they are truth-functional [Read] |
11017 | Some people even claim that conditionals do not express propositions [Read] |
10983 | Knowledge of possible worlds is not causal, but is an ontology entailed by semantics [Read] |
10982 | How can modal Platonists know the truth of a modal proposition? [Read] |
10996 | Actualism is reductionist (to parts of actuality), or moderate realist (accepting real abstractions) [Read] |
10981 | A possible world is a determination of the truth-values of all propositions of a domain [Read] |
11000 | If worlds are concrete, objects can't be present in more than one, and can only have counterparts [Read] |
3490 | Beliefs only make sense as part of a network of other beliefs [Searle] |
3491 | Beliefs are part of a network, and also exist against a background [Searle] |
13480 | Fregean self-evidence is an intrinsic property of basic truths, rules and definitions [Hart,WD] |
13476 | The failure of key assumptions in geometry, mereology and set theory throw doubt on the a priori [Hart,WD] |
3482 | Perception is a function of expectation [Searle] |
3493 | Memory is mainly a guide for current performance [Searle] |
3463 | We don't have a "theory" that other people have minds [Searle] |
3457 | Other minds are not inferred by analogy, but are our best explanation [Searle] |
3480 | We experience unity at an instant and across time [Searle] |
3479 | The mind experiences space, but it is not experienced as spatial [Searle] |
3470 | Conscious creatures seem able to discriminate better [Searle] |
3486 | Unconscious thoughts are those capable of causing conscious ones [Searle] |
3503 | Consciousness results directly from brain processes, not from some intermediary like information [Searle] |
3465 | Either there is intrinsic intentionality, or everything has it [Searle] |
3484 | Water flowing downhill can be described as if it had intentionality [Searle] |
3489 | Intentional phenomena only make sense within a background [Searle] |
3494 | Intentionality is defined in terms of representation [Searle] |
3481 | Consciousness is essential and basic to intentionality [Searle] |
4088 | Pain is not intentional, because it does not represent anything beyond itself [Searle] |
10998 | The mind abstracts ways things might be, which are nonetheless real [Read] |
3467 | Neither introspection nor privileged access makes sense [Searle] |
3483 | Introspection is just thinking about mental states, not a special sort of vision [Searle] |
3468 | I cannot observe my own subjectivity [Searle] |
3469 | Mind and brain don't interact if they are the same [Searle] |
3487 | Without internal content, a zombie's full behaviour couldn't be explained [Searle] |
3458 | Mental states only relate to behaviour contingently, not necessarily [Searle] |
3485 | Wanting H2O only differs from wanting water in its mental component [Searle] |
3461 | Functionalists like the externalist causal theory of reference [Searle] |
3496 | A program for Chinese translation doesn't need to understand Chinese [Searle] |
3499 | Computation presupposes consciousness [Searle] |
3501 | If we are computers, who is the user? [Searle] |
3456 | Consciousness is a brain property as liquidity is a water property [Searle] |
3453 | Property dualism is the reappearance of Cartesianism [Searle] |
3455 | Property dualists tend to find the mind-body problem baffling [Searle] |
3475 | Property dualism denies reductionism [Searle] |
3476 | Mind and brain are supervenient in respect of cause and effect [Searle] |
3477 | If mind-brain supervenience isn't causal, this implies epiphenomenalism [Searle] |
3531 | Mental events can cause even though supervenient, like the solidity of a piston [Searle] |
3478 | Upwards mental causation makes 'supervenience' irrelevant [Searle] |
3466 | Consciousness seems indefinable by conditions or categories [Searle] |
3500 | Can the homunculus fallacy be beaten by recursive decomposition? [Searle] |
9317 | Searle argues that biology explains consciousness, but physics won't explain biology [Searle, by Kriegel/Williford] |
3474 | If mind is caused by brain, does this mean mind IS brain? [Searle] |
3497 | If mind is multiply realisable, it is possible that anything could realise it [Searle] |
3462 | We don't postulate folk psychology, we experience it [Searle] |
3498 | Computation isn't a natural phenomenon, it is a way of seeing phenomena [Searle] |
3492 | Content is much more than just sentence meaning [Searle] |
3464 | There is no such thing as 'wide content' [Searle] |
3506 | We explain behaviour in terms of actual internal representations in the agent [Searle] |
13475 | The Fregean concept of GREEN is a function assigning true to green things, and false to the rest [Hart,WD] |
3451 | Meaning is derived intentionality [Searle] |
3450 | Philosophy of language is a branch of philosophy of mind [Searle] |
3507 | Universal grammar doesn't help us explain anything [Searle] |
11005 | Negative existentials with compositionality make the whole sentence meaningless [Read] |
10966 | A proposition objectifies what a sentence says, as indicative, with secure references [Read] |
3495 | Shared Background makes translation possible, though variation makes it hard [Searle] |
3505 | The function of a heart depends on what we want it to do [Searle] |
3504 | Chemistry entirely explains plant behaviour [Searle] |
3502 | Mind involves fighting, fleeing, feeding and fornicating [Searle] |
3459 | You can only know the limits of knowledge if you know the other side of the limit [Searle] |